springboot Aspect切面

问题描述
配置切面,但未切到目标类上

切面类

@Component
@Aspect
public class ControllerAspect {

    //@Pointcut("execution(* com.yzk.learn.springbootsecurity.controller.UserController.info(..))")
    @Pointcut("execution(* com.learn..*.controller.*.*(..))")
    //@Pointcut("@annotation(org.springframework.web.bind.annotation.GetMapping)")
    public void around(){

    }

    @Around("around()")
    public Object doAround(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
        try{
            Object proceed = proceedingJoinPoint.proceed();
            return proceed;
        }catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }
}

目标类

@RestController
@RequestMapping("/user")
@Slf4j
public class UserController extends ApiController {

    @GetMapping("/info")
    public String info(HttpSession session) {
        
        return null;
    }

源码分析
因代码复杂且分支多,目前截图的顺序是按照从调用链的末端开始,是为了更好的能debug及找到调用线头,不被别的分支代码影响,debug时可以按照文章顺序,非debug可以从后往前看,从后往前是正常的调用顺序

SignaturePattern类
在这里插入图片描述

JoinPointSignature aMethod 目标类
在这里插入图片描述
World world 切面类及表达式
在这里插入图片描述

private FuzzyBoolean matchesExactlyMethod(JoinPointSignature aMethod, World world, boolean subjectMatch) {
		//判断参数是否匹配
		if (parametersCannotMatch(aMethod)) {
			// System.err.println("Parameter types pattern " + parameterTypes + " pcount: " + aMethod.getParameterTypes().length);
			return FuzzyBoolean.NO;
		}
		// OPTIMIZE only for exact match do the pattern match now? Otherwise defer it until other fast checks complete?
		//判断方法名称是否匹配 此处name为* aMethod.getName为info
		if (!name.matches(aMethod.getName())) {
			return FuzzyBoolean.NO;
		}
		// Check the throws pattern
		//判断异常类型是否匹配
		if (subjectMatch && !throwsPattern.matches(aMethod.getExceptions(), world)) {
			return FuzzyBoolean.NO;
		}

		// '*' trivially matches everything, no need to check further
		//判断路径是否匹配
		if (!declaringType.isStar()) {
			if (!declaringType.matchesStatically(aMethod.getDeclaringType().resolve(world))) {
				return FuzzyBoolean.MAYBE;
			}
		}

		// '*' would match any return value
		//判断返回值是否匹配
		if (!returnType.isStar()) {
			boolean b = returnType.isBangVoid();
			if (b) {
				String s = aMethod.getReturnType().getSignature();
				if (s.length() == 1 && s.charAt(0) == 'V') {
					// it is void, so not a match
					return FuzzyBoolean.NO;
				}
			} else {
				if (returnType.isVoid()) {
					String s = aMethod.getReturnType().getSignature();
					if (s.length() != 1 || s.charAt(0) != 'V') {
						// it is not void, so not a match
						return FuzzyBoolean.NO;
					}
				} else {
					if (!returnType.matchesStatically(aMethod.getReturnType().resolve(world))) {
						// looking bad, but there might be parameterization to consider...
						if (!returnType.matchesStatically(aMethod.getGenericReturnType().resolve(world))) {
							// ok, it's bad.
							return FuzzyBoolean.MAYBE;
						}
					}
				}
			}
		}

		// The most simple case: pattern is (..) will match anything
		//参数为(..) 匹配所有参数的方法
		if (parameterTypes.size() == 1 && parameterTypes.get(0).isEllipsis()) {
			return FuzzyBoolean.YES;
		}

		if (!parameterTypes.canMatchSignatureWithNParameters(aMethod.getParameterTypes().length)) {
			return FuzzyBoolean.NO;
		}

		// OPTIMIZE both resolution of these types and their annotations should be deferred - just pass down a world and do it lower
		// down
		// ResolvedType[] resolvedParameters = world.resolve(aMethod.getParameterTypes());

		ResolvableTypeList rtl = new ResolvableTypeList(world, aMethod.getParameterTypes());
		// Only fetch the parameter annotations if the pointcut is going to be matching on them
		ResolvedType[][] parameterAnnotationTypes = null;
		if (isMatchingParameterAnnotations()) {
			parameterAnnotationTypes = aMethod.getParameterAnnotationTypes();
			if (parameterAnnotationTypes != null && parameterAnnotationTypes.length == 0) {
				parameterAnnotationTypes = null;
			}
		}

		if (!parameterTypes.matches(rtl, TypePattern.STATIC, parameterAnnotationTypes).alwaysTrue()) {
			// It could still be a match based on the generic sig parameter types of a parameterized type
			if (!parameterTypes.matches(new ResolvableTypeList(world, aMethod.getGenericParameterTypes()), TypePattern.STATIC,
					parameterAnnotationTypes).alwaysTrue()) {
				return FuzzyBoolean.MAYBE;
				// It could STILL be a match based on the erasure of the parameter types??
				// to be determined via test cases...
			}
		}

		// check that varargs specifications match
		if (!matchesVarArgs(aMethod, world)) {
			return FuzzyBoolean.MAYBE;
		}

		// passed all the guards..
		return FuzzyBoolean.YES;
	}

在else if (kind == Member.METHOD) 处调用上一个方法

private FuzzyBoolean matchesExactly(JoinPointSignature aMember, World inAWorld, boolean allowBridgeMethods, boolean subjectMatch) {
		// Java5 introduces bridge methods, we match a call to them but nothing else...
		if (aMember.isBridgeMethod() && !allowBridgeMethods) {
			return FuzzyBoolean.MAYBE;
		}

		// Only the subject is checked for modifiers
		// see http://www.eclipse.org/aspectj/doc/next/adk15notebook/join-point-modifiers.html
		if (subjectMatch && !modifiers.matches(aMember.getModifiers())) {
			return FuzzyBoolean.NO;
		}

		FuzzyBoolean matchesIgnoringAnnotations = FuzzyBoolean.YES;
		if (kind == Member.STATIC_INITIALIZATION) {
			matchesIgnoringAnnotations = matchesExactlyStaticInitialization(aMember, inAWorld);
		} else if (kind == Member.FIELD) {
			matchesIgnoringAnnotations = matchesExactlyField(aMember, inAWorld);
		} else if (kind == Member.METHOD) {
			//上个方法调用处
			matchesIgnoringAnnotations = matchesExactlyMethod(aMember, inAWorld, subjectMatch);
		} else if (kind == Member.CONSTRUCTOR) {
			matchesIgnoringAnnotations = matchesExactlyConstructor(aMember, inAWorld);
		}
		if (matchesIgnoringAnnotations.alwaysFalse()) {
			return FuzzyBoolean.NO;
		}

		// Only the subject is checked for annotations (239441/119749)
		// see http://www.eclipse.org/aspectj/doc/next/adk15notebook/join-point-modifiers.html
		if (subjectMatch) {
			// The annotations must match if specified
			if (!matchesAnnotations(aMember, inAWorld).alwaysTrue()) {
				return FuzzyBoolean.NO;
			} else {
				return matchesIgnoringAnnotations;
			}
		} else {
			// Unless they specified any annotation then it is a failure
			if (annotationPattern instanceof AnyAnnotationTypePattern) {
				return matchesIgnoringAnnotations;
			} else {
				return FuzzyBoolean.NO;
			}
		}

		// if (subjectMatch && !matchesAnnotations(aMember, inAWorld).alwaysTrue()) {
		// return FuzzyBoolean.NO;
		// } else {
		//			
		// return matchesIgnoringAnnotations;
		// }

	}

在FuzzyBoolean matchResult = matchesExactly(aSig, world, allowBridgeMethods, subjectMatch);处调用上一个方法

public boolean matches(Member joinPointSignature, World world, boolean allowBridgeMethods) {
		// fail (or succeed!) fast tests...
		if (joinPointSignature == null) {
			return false;
		}
		if (kind != joinPointSignature.getKind()) {
			return false;
		}
		if (kind == Member.ADVICE) {
			return true;
		}

		// do the hard work then...
		boolean subjectMatch = true;
		boolean wantsAnnotationMatch = wantToMatchAnnotationPattern();
		JoinPointSignatureIterator candidateMatches = joinPointSignature.getJoinPointSignatures(world);
		while (candidateMatches.hasNext()) {
			JoinPointSignature aSig = candidateMatches.next();
			// System.out.println(aSig);
			FuzzyBoolean matchResult = matchesExactly(aSig, world, allowBridgeMethods, subjectMatch);
			if (matchResult.alwaysTrue()) {
				return true;
			} else if (matchResult.alwaysFalse()) {
				return false;
			}
			// if we got a "MAYBE" it's worth looking at the other signatures
			// The first signature is the subject signature - and against it we must match modifiers/annotations/throws
			// see http://www.eclipse.org/aspectj/doc/next/adk15notebook/join-point-modifiers.html
			subjectMatch = false;
			// Early exit
			if (wantsAnnotationMatch) {
				return false;
			}
		}
		return false;
	}

KindedPointcut类

在!signature.matches(shadow.getMatchingSignature(), shadow.getIWorld(), this.kind == Shadow.MethodCall)) 处调用上一个方法

protected FuzzyBoolean matchInternal(Shadow shadow) {
		if (shadow.getKind() != kind) {
			return FuzzyBoolean.NO;
		}

		if (shadow.getKind() == Shadow.SynchronizationLock && kind == Shadow.SynchronizationLock) {
			return FuzzyBoolean.YES;
		}
		if (shadow.getKind() == Shadow.SynchronizationUnlock && kind == Shadow.SynchronizationUnlock) {
			return FuzzyBoolean.YES;
		}

		if (!signature.matches(shadow.getMatchingSignature(), shadow.getIWorld(), this.kind == Shadow.MethodCall)) {

			if (kind == Shadow.MethodCall) {
				warnOnConfusingSig(shadow);
				// warnOnBridgeMethod(shadow);
			}
			return FuzzyBoolean.NO;
		}

		return FuzzyBoolean.YES;
	}

Pointcut类
在ret = matchInternal(shadow);处调用上一个方法

public final FuzzyBoolean match(Shadow shadow) {
		if (shadow.shadowId == lastMatchedShadowId) {
			return lastMatchedShadowResult;
		}
		FuzzyBoolean ret;
		// this next test will prevent a lot of un-needed matching going on....
		if (shadow.getKind().isSet(couldMatchKinds())) {
			ret = matchInternal(shadow);
		} else {
			ret = FuzzyBoolean.NO;
		}
		lastMatchedShadowId = shadow.shadowId;
		lastMatchedShadowResult = ret;
		return ret;
	}

PointcutExpressionImpl类
在org.aspectj.util.FuzzyBoolean match = pointcut.match(forShadow);处调用上一个方法

private ShadowMatchImpl getShadowMatch(Shadow forShadow) {
		org.aspectj.util.FuzzyBoolean match = pointcut.match(forShadow);
		Test residueTest = Literal.TRUE;
		ExposedState state = getExposedState();
		if (match.maybeTrue()) {
			residueTest = pointcut.findResidue(forShadow, state);
		}
		ShadowMatchImpl sm = new ShadowMatchImpl(match, residueTest, state, parameters);
		sm.setMatchingContext(this.matchContext);
		return sm;
	}

在ShadowMatchImpl sm = getShadowMatch(s);处调用上一个方法

private ShadowMatch matchesExecution(Member aMember) {
		Shadow s = ReflectionShadow.makeExecutionShadow(world, aMember, this.matchContext);
		ShadowMatchImpl sm = getShadowMatch(s);
		sm.setSubject(aMember);
		sm.setWithinCode(null);
		sm.setWithinType(aMember.getDeclaringClass());
		return sm;
	}

在ShadowMatch match = matchesExecution(aMethod);处调用上一个方法

public ShadowMatch matchesMethodExecution(Method aMethod) {
		ShadowMatch match = matchesExecution(aMethod);
		if (MATCH_INFO && match.maybeMatches()) {
			System.out.println("MATCHINFO: method execution match on '" + aMethod + "' for '" + this.expression + "': "
					+ (match.alwaysMatches() ? "YES" : "MAYBE"));
		}
		return match;
	}

AspectJExpressionPointcut类
在shadowMatch = obtainPointcutExpression().matchesMethodExecution(methodToMatch);处调用上一个方法

private ShadowMatch getShadowMatch(Method targetMethod, Method originalMethod) {
		// Avoid lock contention for known Methods through concurrent access...
		ShadowMatch shadowMatch = this.shadowMatchCache.get(targetMethod);
		if (shadowMatch == null) {
			synchronized (this.shadowMatchCache) {
				// Not found - now check again with full lock...
				PointcutExpression fallbackExpression = null;
				shadowMatch = this.shadowMatchCache.get(targetMethod);
				if (shadowMatch == null) {
					Method methodToMatch = targetMethod;
					try {
						try {
							shadowMatch = obtainPointcutExpression().matchesMethodExecution(methodToMatch);
						}
						catch (ReflectionWorldException ex) {
							// Failed to introspect target method, probably because it has been loaded
							// in a special ClassLoader. Let's try the declaring ClassLoader instead...
							try {
								fallbackExpression = getFallbackPointcutExpression(methodToMatch.getDeclaringClass());
								if (fallbackExpression != null) {
									shadowMatch = fallbackExpression.matchesMethodExecution(methodToMatch);
								}
							}
							catch (ReflectionWorldException ex2) {
								fallbackExpression = null;
							}
						}
						if (targetMethod != originalMethod && (shadowMatch == null ||
								(shadowMatch.neverMatches() && Proxy.isProxyClass(targetMethod.getDeclaringClass())))) {
							// Fall back to the plain original method in case of no resolvable match or a
							// negative match on a proxy class (which doesn't carry any annotations on its
							// redeclared methods).
							methodToMatch = originalMethod;
							try {
								shadowMatch = obtainPointcutExpression().matchesMethodExecution(methodToMatch);
							}
							catch (ReflectionWorldException ex) {
								// Could neither introspect the target class nor the proxy class ->
								// let's try the original method's declaring class before we give up...
								try {
									fallbackExpression = getFallbackPointcutExpression(methodToMatch.getDeclaringClass());
									if (fallbackExpression != null) {
										shadowMatch = fallbackExpression.matchesMethodExecution(methodToMatch);
									}
								}
								catch (ReflectionWorldException ex2) {
									fallbackExpression = null;
								}
							}
						}
					}
					catch (Throwable ex) {
						// Possibly AspectJ 1.8.10 encountering an invalid signature
						logger.debug("PointcutExpression matching rejected target method", ex);
						fallbackExpression = null;
					}
					if (shadowMatch == null) {
						shadowMatch = new ShadowMatchImpl(org.aspectj.util.FuzzyBoolean.NO, null, null, null);
					}
					else if (shadowMatch.maybeMatches() && fallbackExpression != null) {
						shadowMatch = new DefensiveShadowMatch(shadowMatch,
								fallbackExpression.matchesMethodExecution(methodToMatch));
					}
					this.shadowMatchCache.put(targetMethod, shadowMatch);
				}
			}
		}
		return shadowMatch;
	}

在return getShadowMatch(targetMethod, method);处调用上一个方法

private ShadowMatch getTargetShadowMatch(Method method, Class<?> targetClass) {
		Method targetMethod = AopUtils.getMostSpecificMethod(method, targetClass);
		if (targetMethod.getDeclaringClass().isInterface()) {
			// Try to build the most specific interface possible for inherited methods to be
			// considered for sub-interface matches as well, in particular for proxy classes.
			// Note: AspectJ is only going to take Method.getDeclaringClass() into account.
			Set<Class<?>> ifcs = ClassUtils.getAllInterfacesForClassAsSet(targetClass);
			if (ifcs.size() > 1) {
				try {
					Class<?> compositeInterface = ClassUtils.createCompositeInterface(
							ClassUtils.toClassArray(ifcs), targetClass.getClassLoader());
					targetMethod = ClassUtils.getMostSpecificMethod(targetMethod, compositeInterface);
				}
				catch (IllegalArgumentException ex) {
					// Implemented interfaces probably expose conflicting method signatures...
					// Proceed with original target method.
				}
			}
		}
		return getShadowMatch(targetMethod, method);
	}

在ShadowMatch shadowMatch = getTargetShadowMatch(method, targetClass);处调用上一个方法

public boolean matches(Method method, Class<?> targetClass, boolean hasIntroductions) {
		obtainPointcutExpression();
		ShadowMatch shadowMatch = getTargetShadowMatch(method, targetClass);

		// Special handling for this, target, @this, @target, @annotation
		// in Spring - we can optimize since we know we have exactly this class,
		// and there will never be matching subclass at runtime.
		if (shadowMatch.alwaysMatches()) {
			return true;
		}
		else if (shadowMatch.neverMatches()) {
			return false;
		}
		else {
			// the maybe case
			if (hasIntroductions) {
				return true;
			}
			// A match test returned maybe - if there are any subtype sensitive variables
			// involved in the test (this, target, at_this, at_target, at_annotation) then
			// we say this is not a match as in Spring there will never be a different
			// runtime subtype.
			RuntimeTestWalker walker = getRuntimeTestWalker(shadowMatch);
			return (!walker.testsSubtypeSensitiveVars() || walker.testTargetInstanceOfResidue(targetClass));
		}
	}

AopUtils类
在(introductionAwareMethodMatcher != null ?
introductionAwareMethodMatcher.matches(method, targetClass, hasIntroductions) :
methodMatcher.matches(method, targetClass))处调用上一个方法

public static boolean canApply(Pointcut pc, Class<?> targetClass, boolean hasIntroductions) {
		Assert.notNull(pc, "Pointcut must not be null");
		if (!pc.getClassFilter().matches(targetClass)) {
			return false;
		}

		MethodMatcher methodMatcher = pc.getMethodMatcher();
		if (methodMatcher == MethodMatcher.TRUE) {
			// No need to iterate the methods if we're matching any method anyway...
			return true;
		}

		IntroductionAwareMethodMatcher introductionAwareMethodMatcher = null;
		if (methodMatcher instanceof IntroductionAwareMethodMatcher) {
			introductionAwareMethodMatcher = (IntroductionAwareMethodMatcher) methodMatcher;
		}

		Set<Class<?>> classes = new LinkedHashSet<>();
		if (!Proxy.isProxyClass(targetClass)) {
			classes.add(ClassUtils.getUserClass(targetClass));
		}
		classes.addAll(ClassUtils.getAllInterfacesForClassAsSet(targetClass));

		for (Class<?> clazz : classes) {
			Method[] methods = ReflectionUtils.getAllDeclaredMethods(clazz);
			for (Method method : methods) {
				if (introductionAwareMethodMatcher != null ?
						introductionAwareMethodMatcher.matches(method, targetClass, hasIntroductions) :
						methodMatcher.matches(method, targetClass)) {
					return true;
				}
			}
		}

		return false;
	}

在return canApply(pca.getPointcut(), targetClass, hasIntroductions);调用上一个方法

public static boolean canApply(Advisor advisor, Class<?> targetClass, boolean hasIntroductions) {
		if (advisor instanceof IntroductionAdvisor) {
			return ((IntroductionAdvisor) advisor).getClassFilter().matches(targetClass);
		}
		else if (advisor instanceof PointcutAdvisor) {
			PointcutAdvisor pca = (PointcutAdvisor) advisor;
			return canApply(pca.getPointcut(), targetClass, hasIntroductions);
		}
		else {
			// It doesn't have a pointcut so we assume it applies.
			return true;
		}
	}

在canApply(candidate, clazz, hasIntroductions)处调用上一个方法

public static List<Advisor> findAdvisorsThatCanApply(List<Advisor> candidateAdvisors, Class<?> clazz) {
		if (candidateAdvisors.isEmpty()) {
			return candidateAdvisors;
		}
		List<Advisor> eligibleAdvisors = new ArrayList<>();
		for (Advisor candidate : candidateAdvisors) {
			if (candidate instanceof IntroductionAdvisor && canApply(candidate, clazz)) {
				eligibleAdvisors.add(candidate);
			}
		}
		boolean hasIntroductions = !eligibleAdvisors.isEmpty();
		for (Advisor candidate : candidateAdvisors) {
			if (candidate instanceof IntroductionAdvisor) {
				// already processed
				continue;
			}
			if (canApply(candidate, clazz, hasIntroductions)) {
				eligibleAdvisors.add(candidate);
			}
		}
		return eligibleAdvisors;
	}

AbstractAdvisorAutoProxyCreator类
在return AopUtils.findAdvisorsThatCanApply(candidateAdvisors, beanClass);处调用上一个方法

protected List<Advisor> findAdvisorsThatCanApply(
			List<Advisor> candidateAdvisors, Class<?> beanClass, String beanName) {

		ProxyCreationContext.setCurrentProxiedBeanName(beanName);
		try {
			return AopUtils.findAdvisorsThatCanApply(candidateAdvisors, beanClass);
		}
		finally {
			ProxyCreationContext.setCurrentProxiedBeanName(null);
		}
	}

在List eligibleAdvisors = findAdvisorsThatCanApply(candidateAdvisors, beanClass, beanName);处调用上一个方法

protected List<Advisor> findEligibleAdvisors(Class<?> beanClass, String beanName) {
		List<Advisor> candidateAdvisors = findCandidateAdvisors();
		List<Advisor> eligibleAdvisors = findAdvisorsThatCanApply(candidateAdvisors, beanClass, beanName);
		extendAdvisors(eligibleAdvisors);
		if (!eligibleAdvisors.isEmpty()) {
			eligibleAdvisors = sortAdvisors(eligibleAdvisors);
		}
		return eligibleAdvisors;
	}

在List advisors = findEligibleAdvisors(beanClass, beanName);处调用上一个方法

protected Object[] getAdvicesAndAdvisorsForBean(
			Class<?> beanClass, String beanName, @Nullable TargetSource targetSource) {

		List<Advisor> advisors = findEligibleAdvisors(beanClass, beanName);
		if (advisors.isEmpty()) {
			return DO_NOT_PROXY;
		}
		return advisors.toArray();
	}

AbstractAutoProxyCreator类
在Object[] specificInterceptors = getAdvicesAndAdvisorsForBean(bean.getClass(), beanName, null);处调用上一个方法

此处需要关注的地方就是
Object proxy = createProxy(
bean.getClass(), beanName, specificInterceptors, new SingletonTargetSource(bean));
this.proxyTypes.put(cacheKey, proxy.getClass());
生成了相应的代理类

protected Object wrapIfNecessary(Object bean, String beanName, Object cacheKey) {
		if (StringUtils.hasLength(beanName) && this.targetSourcedBeans.contains(beanName)) {
			return bean;
		}
		if (Boolean.FALSE.equals(this.advisedBeans.get(cacheKey))) {
			return bean;
		}
		if (isInfrastructureClass(bean.getClass()) || shouldSkip(bean.getClass(), beanName)) {
			this.advisedBeans.put(cacheKey, Boolean.FALSE);
			return bean;
		}

		// Create proxy if we have advice.
		Object[] specificInterceptors = getAdvicesAndAdvisorsForBean(bean.getClass(), beanName, null);
		if (specificInterceptors != DO_NOT_PROXY) {
			this.advisedBeans.put(cacheKey, Boolean.TRUE);
			Object proxy = createProxy(
					bean.getClass(), beanName, specificInterceptors, new SingletonTargetSource(bean));
			this.proxyTypes.put(cacheKey, proxy.getClass());
			return proxy;
		}

		this.advisedBeans.put(cacheKey, Boolean.FALSE);
		return bean;
	}

在return wrapIfNecessary(bean, beanName, cacheKey);处调用上一个方法

public Object postProcessAfterInitialization(@Nullable Object bean, String beanName) {
		if (bean != null) {
			Object cacheKey = getCacheKey(bean.getClass(), beanName);
			if (this.earlyProxyReferences.remove(cacheKey) != bean) {
				return wrapIfNecessary(bean, beanName, cacheKey);
			}
		}
		return bean;
	}

AbstractAutowireCapableBeanFactory类
在Object current = processor.postProcessAfterInitialization(result, beanName);处调用上一个方法

public Object applyBeanPostProcessorsAfterInitialization(Object existingBean, String beanName)
			throws BeansException {

		Object result = existingBean;
		for (BeanPostProcessor processor : getBeanPostProcessors()) {
			Object current = processor.postProcessAfterInitialization(result, beanName);
			if (current == null) {
				return result;
			}
			result = current;
		}
		return result;
	}

在wrappedBean = applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName);处调用上一个方法

protected Object initializeBean(String beanName, Object bean, @Nullable RootBeanDefinition mbd) {
		if (System.getSecurityManager() != null) {
			AccessController.doPrivileged((PrivilegedAction<Object>) () -> {
				invokeAwareMethods(beanName, bean);
				return null;
			}, getAccessControlContext());
		}
		else {
			invokeAwareMethods(beanName, bean);
		}

		Object wrappedBean = bean;
		if (mbd == null || !mbd.isSynthetic()) {
			wrappedBean = applyBeanPostProcessorsBeforeInitialization(wrappedBean, beanName);
		}

		try {
			invokeInitMethods(beanName, wrappedBean, mbd);
		}
		catch (Throwable ex) {
			throw new BeanCreationException(
					(mbd != null ? mbd.getResourceDescription() : null),
					beanName, "Invocation of init method failed", ex);
		}
		if (mbd == null || !mbd.isSynthetic()) {
			wrappedBean = applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName);
		}

		return wrappedBean;
	}

在exposedObject = initializeBean(beanName, exposedObject, mbd);处调用上一个方法

protected Object doCreateBean(String beanName, RootBeanDefinition mbd, @Nullable Object[] args)
			throws BeanCreationException {

		// Instantiate the bean.
		BeanWrapper instanceWrapper = null;
		if (mbd.isSingleton()) {
			instanceWrapper = this.factoryBeanInstanceCache.remove(beanName);
		}
		if (instanceWrapper == null) {
			instanceWrapper = createBeanInstance(beanName, mbd, args);
		}
		Object bean = instanceWrapper.getWrappedInstance();
		Class<?> beanType = instanceWrapper.getWrappedClass();
		if (beanType != NullBean.class) {
			mbd.resolvedTargetType = beanType;
		}

		// Allow post-processors to modify the merged bean definition.
		synchronized (mbd.postProcessingLock) {
			if (!mbd.postProcessed) {
				try {
					applyMergedBeanDefinitionPostProcessors(mbd, beanType, beanName);
				}
				catch (Throwable ex) {
					throw new BeanCreationException(mbd.getResourceDescription(), beanName,
							"Post-processing of merged bean definition failed", ex);
				}
				mbd.postProcessed = true;
			}
		}

		// Eagerly cache singletons to be able to resolve circular references
		// even when triggered by lifecycle interfaces like BeanFactoryAware.
		boolean earlySingletonExposure = (mbd.isSingleton() && this.allowCircularReferences &&
				isSingletonCurrentlyInCreation(beanName));
		if (earlySingletonExposure) {
			if (logger.isTraceEnabled()) {
				logger.trace("Eagerly caching bean '" + beanName +
						"' to allow for resolving potential circular references");
			}
			addSingletonFactory(beanName, () -> getEarlyBeanReference(beanName, mbd, bean));
		}

		// Initialize the bean instance.
		Object exposedObject = bean;
		try {
			populateBean(beanName, mbd, instanceWrapper);
			exposedObject = initializeBean(beanName, exposedObject, mbd);
		}
		catch (Throwable ex) {
			if (ex instanceof BeanCreationException && beanName.equals(((BeanCreationException) ex).getBeanName())) {
				throw (BeanCreationException) ex;
			}
			else {
				throw new BeanCreationException(
						mbd.getResourceDescription(), beanName, "Initialization of bean failed", ex);
			}
		}

		if (earlySingletonExposure) {
			Object earlySingletonReference = getSingleton(beanName, false);
			if (earlySingletonReference != null) {
				if (exposedObject == bean) {
					exposedObject = earlySingletonReference;
				}
				else if (!this.allowRawInjectionDespiteWrapping && hasDependentBean(beanName)) {
					String[] dependentBeans = getDependentBeans(beanName);
					Set<String> actualDependentBeans = new LinkedHashSet<>(dependentBeans.length);
					for (String dependentBean : dependentBeans) {
						if (!removeSingletonIfCreatedForTypeCheckOnly(dependentBean)) {
							actualDependentBeans.add(dependentBean);
						}
					}
					if (!actualDependentBeans.isEmpty()) {
						throw new BeanCurrentlyInCreationException(beanName,
								"Bean with name '" + beanName + "' has been injected into other beans [" +
								StringUtils.collectionToCommaDelimitedString(actualDependentBeans) +
								"] in its raw version as part of a circular reference, but has eventually been " +
								"wrapped. This means that said other beans do not use the final version of the " +
								"bean. This is often the result of over-eager type matching - consider using " +
								"'getBeanNamesForType' with the 'allowEagerInit' flag turned off, for example.");
					}
				}
			}
		}

		// Register bean as disposable.
		try {
			registerDisposableBeanIfNecessary(beanName, bean, mbd);
		}
		catch (BeanDefinitionValidationException ex) {
			throw new BeanCreationException(
					mbd.getResourceDescription(), beanName, "Invalid destruction signature", ex);
		}

		return exposedObject;
	}

在Object beanInstance = doCreateBean(beanName, mbdToUse, args);处调用上一个方法

@Override
	protected Object createBean(String beanName, RootBeanDefinition mbd, @Nullable Object[] args)
			throws BeanCreationException {

		if (logger.isTraceEnabled()) {
			logger.trace("Creating instance of bean '" + beanName + "'");
		}
		RootBeanDefinition mbdToUse = mbd;

		// Make sure bean class is actually resolved at this point, and
		// clone the bean definition in case of a dynamically resolved Class
		// which cannot be stored in the shared merged bean definition.
		Class<?> resolvedClass = resolveBeanClass(mbd, beanName);
		if (resolvedClass != null && !mbd.hasBeanClass() && mbd.getBeanClassName() != null) {
			mbdToUse = new RootBeanDefinition(mbd);
			mbdToUse.setBeanClass(resolvedClass);
		}

		// Prepare method overrides.
		try {
			mbdToUse.prepareMethodOverrides();
		}
		catch (BeanDefinitionValidationException ex) {
			throw new BeanDefinitionStoreException(mbdToUse.getResourceDescription(),
					beanName, "Validation of method overrides failed", ex);
		}

		try {
			// Give BeanPostProcessors a chance to return a proxy instead of the target bean instance.
			Object bean = resolveBeforeInstantiation(beanName, mbdToUse);
			if (bean != null) {
				return bean;
			}
		}
		catch (Throwable ex) {
			throw new BeanCreationException(mbdToUse.getResourceDescription(), beanName,
					"BeanPostProcessor before instantiation of bean failed", ex);
		}

		try {
			Object beanInstance = doCreateBean(beanName, mbdToUse, args);
			if (logger.isTraceEnabled()) {
				logger.trace("Finished creating instance of bean '" + beanName + "'");
			}
			return beanInstance;
		}
		catch (BeanCreationException | ImplicitlyAppearedSingletonException ex) {
			// A previously detected exception with proper bean creation context already,
			// or illegal singleton state to be communicated up to DefaultSingletonBeanRegistry.
			throw ex;
		}
		catch (Throwable ex) {
			throw new BeanCreationException(
					mbdToUse.getResourceDescription(), beanName, "Unexpected exception during bean creation", ex);
		}
	}

DefaultSingletonBeanRegistry类
在singletonObject = singletonFactory.getObject();处调用上面的方法

public Object getSingleton(String beanName, ObjectFactory<?> singletonFactory) {
		Assert.notNull(beanName, "Bean name must not be null");
		synchronized (this.singletonObjects) {
			Object singletonObject = this.singletonObjects.get(beanName);
			if (singletonObject == null) {
				if (this.singletonsCurrentlyInDestruction) {
					throw new BeanCreationNotAllowedException(beanName,
							"Singleton bean creation not allowed while singletons of this factory are in destruction " +
							"(Do not request a bean from a BeanFactory in a destroy method implementation!)");
				}
				if (logger.isDebugEnabled()) {
					logger.debug("Creating shared instance of singleton bean '" + beanName + "'");
				}
				beforeSingletonCreation(beanName);
				boolean newSingleton = false;
				boolean recordSuppressedExceptions = (this.suppressedExceptions == null);
				if (recordSuppressedExceptions) {
					this.suppressedExceptions = new LinkedHashSet<>();
				}
				try {
					singletonObject = singletonFactory.getObject();
					newSingleton = true;
				}
				catch (IllegalStateException ex) {
					// Has the singleton object implicitly appeared in the meantime ->
					// if yes, proceed with it since the exception indicates that state.
					singletonObject = this.singletonObjects.get(beanName);
					if (singletonObject == null) {
						throw ex;
					}
				}
				catch (BeanCreationException ex) {
					if (recordSuppressedExceptions) {
						for (Exception suppressedException : this.suppressedExceptions) {
							ex.addRelatedCause(suppressedException);
						}
					}
					throw ex;
				}
				finally {
					if (recordSuppressedExceptions) {
						this.suppressedExceptions = null;
					}
					afterSingletonCreation(beanName);
				}
				if (newSingleton) {
					addSingleton(beanName, singletonObject);
				}
			}
			return singletonObject;
		}
	}

AbstractBeanFactory类
在sharedInstance = getSingleton(beanName, () ->{})处调用上一个方法 此处需要注意,是在匿名内部类中的执行

protected <T> T doGetBean(
			String name, @Nullable Class<T> requiredType, @Nullable Object[] args, boolean typeCheckOnly)
			throws BeansException {

		String beanName = transformedBeanName(name);
		Object beanInstance;

		// Eagerly check singleton cache for manually registered singletons.
		Object sharedInstance = getSingleton(beanName);
		if (sharedInstance != null && args == null) {
			if (logger.isTraceEnabled()) {
				if (isSingletonCurrentlyInCreation(beanName)) {
					logger.trace("Returning eagerly cached instance of singleton bean '" + beanName +
							"' that is not fully initialized yet - a consequence of a circular reference");
				}
				else {
					logger.trace("Returning cached instance of singleton bean '" + beanName + "'");
				}
			}
			beanInstance = getObjectForBeanInstance(sharedInstance, name, beanName, null);
		}

		else {
			// Fail if we're already creating this bean instance:
			// We're assumably within a circular reference.
			if (isPrototypeCurrentlyInCreation(beanName)) {
				throw new BeanCurrentlyInCreationException(beanName);
			}

			// Check if bean definition exists in this factory.
			BeanFactory parentBeanFactory = getParentBeanFactory();
			if (parentBeanFactory != null && !containsBeanDefinition(beanName)) {
				// Not found -> check parent.
				String nameToLookup = originalBeanName(name);
				if (parentBeanFactory instanceof AbstractBeanFactory) {
					return ((AbstractBeanFactory) parentBeanFactory).doGetBean(
							nameToLookup, requiredType, args, typeCheckOnly);
				}
				else if (args != null) {
					// Delegation to parent with explicit args.
					return (T) parentBeanFactory.getBean(nameToLookup, args);
				}
				else if (requiredType != null) {
					// No args -> delegate to standard getBean method.
					return parentBeanFactory.getBean(nameToLookup, requiredType);
				}
				else {
					return (T) parentBeanFactory.getBean(nameToLookup);
				}
			}

			if (!typeCheckOnly) {
				markBeanAsCreated(beanName);
			}

			StartupStep beanCreation = this.applicationStartup.start("spring.beans.instantiate")
					.tag("beanName", name);
			try {
				if (requiredType != null) {
					beanCreation.tag("beanType", requiredType::toString);
				}
				RootBeanDefinition mbd = getMergedLocalBeanDefinition(beanName);
				checkMergedBeanDefinition(mbd, beanName, args);

				// Guarantee initialization of beans that the current bean depends on.
				String[] dependsOn = mbd.getDependsOn();
				if (dependsOn != null) {
					for (String dep : dependsOn) {
						if (isDependent(beanName, dep)) {
							throw new BeanCreationException(mbd.getResourceDescription(), beanName,
									"Circular depends-on relationship between '" + beanName + "' and '" + dep + "'");
						}
						registerDependentBean(dep, beanName);
						try {
							getBean(dep);
						}
						catch (NoSuchBeanDefinitionException ex) {
							throw new BeanCreationException(mbd.getResourceDescription(), beanName,
									"'" + beanName + "' depends on missing bean '" + dep + "'", ex);
						}
					}
				}

				// Create bean instance.
				if (mbd.isSingleton()) {
					sharedInstance = getSingleton(beanName, () -> {
						try {
							return createBean(beanName, mbd, args);
						}
						catch (BeansException ex) {
							// Explicitly remove instance from singleton cache: It might have been put there
							// eagerly by the creation process, to allow for circular reference resolution.
							// Also remove any beans that received a temporary reference to the bean.
							destroySingleton(beanName);
							throw ex;
						}
					});
					beanInstance = getObjectForBeanInstance(sharedInstance, name, beanName, mbd);
				}

				else if (mbd.isPrototype()) {
					// It's a prototype -> create a new instance.
					Object prototypeInstance = null;
					try {
						beforePrototypeCreation(beanName);
						prototypeInstance = createBean(beanName, mbd, args);
					}
					finally {
						afterPrototypeCreation(beanName);
					}
					beanInstance = getObjectForBeanInstance(prototypeInstance, name, beanName, mbd);
				}

				else {
					String scopeName = mbd.getScope();
					if (!StringUtils.hasLength(scopeName)) {
						throw new IllegalStateException("No scope name defined for bean '" + beanName + "'");
					}
					Scope scope = this.scopes.get(scopeName);
					if (scope == null) {
						throw new IllegalStateException("No Scope registered for scope name '" + scopeName + "'");
					}
					try {
						Object scopedInstance = scope.get(beanName, () -> {
							beforePrototypeCreation(beanName);
							try {
								return createBean(beanName, mbd, args);
							}
							finally {
								afterPrototypeCreation(beanName);
							}
						});
						beanInstance = getObjectForBeanInstance(scopedInstance, name, beanName, mbd);
					}
					catch (IllegalStateException ex) {
						throw new ScopeNotActiveException(beanName, scopeName, ex);
					}
				}
			}
			catch (BeansException ex) {
				beanCreation.tag("exception", ex.getClass().toString());
				beanCreation.tag("message", String.valueOf(ex.getMessage()));
				cleanupAfterBeanCreationFailure(beanName);
				throw ex;
			}
			finally {
				beanCreation.end();
			}
		}

		return adaptBeanInstance(name, beanInstance, requiredType);
	}
public Object getBean(String name) throws BeansException {
		return doGetBean(name, null, null, false);
	}

DefaultListableBeanFactory类
在getBean(beanName);处调用上一个方法

public void preInstantiateSingletons() throws BeansException {
		if (logger.isTraceEnabled()) {
			logger.trace("Pre-instantiating singletons in " + this);
		}

		// Iterate over a copy to allow for init methods which in turn register new bean definitions.
		// While this may not be part of the regular factory bootstrap, it does otherwise work fine.
		List<String> beanNames = new ArrayList<>(this.beanDefinitionNames);

		// Trigger initialization of all non-lazy singleton beans...
		for (String beanName : beanNames) {
			RootBeanDefinition bd = getMergedLocalBeanDefinition(beanName);
			if (!bd.isAbstract() && bd.isSingleton() && !bd.isLazyInit()) {
				if (isFactoryBean(beanName)) {
					Object bean = getBean(FACTORY_BEAN_PREFIX + beanName);
					if (bean instanceof FactoryBean) {
						FactoryBean<?> factory = (FactoryBean<?>) bean;
						boolean isEagerInit;
						if (System.getSecurityManager() != null && factory instanceof SmartFactoryBean) {
							isEagerInit = AccessController.doPrivileged(
									(PrivilegedAction<Boolean>) ((SmartFactoryBean<?>) factory)::isEagerInit,
									getAccessControlContext());
						}
						else {
							isEagerInit = (factory instanceof SmartFactoryBean &&
									((SmartFactoryBean<?>) factory).isEagerInit());
						}
						if (isEagerInit) {
							getBean(beanName);
						}
					}
				}
				else {
					getBean(beanName);
				}
			}
		}

		// Trigger post-initialization callback for all applicable beans...
		for (String beanName : beanNames) {
			Object singletonInstance = getSingleton(beanName);
			if (singletonInstance instanceof SmartInitializingSingleton) {
				StartupStep smartInitialize = this.getApplicationStartup().start("spring.beans.smart-initialize")
						.tag("beanName", beanName);
				SmartInitializingSingleton smartSingleton = (SmartInitializingSingleton) singletonInstance;
				if (System.getSecurityManager() != null) {
					AccessController.doPrivileged((PrivilegedAction<Object>) () -> {
						smartSingleton.afterSingletonsInstantiated();
						return null;
					}, getAccessControlContext());
				}
				else {
					smartSingleton.afterSingletonsInstantiated();
				}
				smartInitialize.end();
			}
		}
	}

AbstractApplicationContext类
在beanFactory.preInstantiateSingletons();处调用上一个方法

protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory beanFactory) {
		// Initialize conversion service for this context.
		if (beanFactory.containsBean(CONVERSION_SERVICE_BEAN_NAME) &&
				beanFactory.isTypeMatch(CONVERSION_SERVICE_BEAN_NAME, ConversionService.class)) {
			beanFactory.setConversionService(
					beanFactory.getBean(CONVERSION_SERVICE_BEAN_NAME, ConversionService.class));
		}

		// Register a default embedded value resolver if no BeanFactoryPostProcessor
		// (such as a PropertySourcesPlaceholderConfigurer bean) registered any before:
		// at this point, primarily for resolution in annotation attribute values.
		if (!beanFactory.hasEmbeddedValueResolver()) {
			beanFactory.addEmbeddedValueResolver(strVal -> getEnvironment().resolvePlaceholders(strVal));
		}

		// Initialize LoadTimeWeaverAware beans early to allow for registering their transformers early.
		String[] weaverAwareNames = beanFactory.getBeanNamesForType(LoadTimeWeaverAware.class, false, false);
		for (String weaverAwareName : weaverAwareNames) {
			getBean(weaverAwareName);
		}

		// Stop using the temporary ClassLoader for type matching.
		beanFactory.setTempClassLoader(null);

		// Allow for caching all bean definition metadata, not expecting further changes.
		beanFactory.freezeConfiguration();

		// Instantiate all remaining (non-lazy-init) singletons.
		beanFactory.preInstantiateSingletons();
	}

在finishBeanFactoryInitialization(beanFactory);处调用上一个方法

public void refresh() throws BeansException, IllegalStateException {
		synchronized (this.startupShutdownMonitor) {
			StartupStep contextRefresh = this.applicationStartup.start("spring.context.refresh");

			// Prepare this context for refreshing.
			prepareRefresh();

			// Tell the subclass to refresh the internal bean factory.
			ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();

			// Prepare the bean factory for use in this context.
			prepareBeanFactory(beanFactory);

			try {
				// Allows post-processing of the bean factory in context subclasses.
				postProcessBeanFactory(beanFactory);

				StartupStep beanPostProcess = this.applicationStartup.start("spring.context.beans.post-process");
				// Invoke factory processors registered as beans in the context.
				invokeBeanFactoryPostProcessors(beanFactory);

				// Register bean processors that intercept bean creation.
				registerBeanPostProcessors(beanFactory);
				beanPostProcess.end();

				// Initialize message source for this context.
				initMessageSource();

				// Initialize event multicaster for this context.
				initApplicationEventMulticaster();

				// Initialize other special beans in specific context subclasses.
				onRefresh();

				// Check for listener beans and register them.
				registerListeners();

				// Instantiate all remaining (non-lazy-init) singletons.
				finishBeanFactoryInitialization(beanFactory);

				// Last step: publish corresponding event.
				finishRefresh();
			}

			catch (BeansException ex) {
				if (logger.isWarnEnabled()) {
					logger.warn("Exception encountered during context initialization - " +
							"cancelling refresh attempt: " + ex);
				}

				// Destroy already created singletons to avoid dangling resources.
				destroyBeans();

				// Reset 'active' flag.
				cancelRefresh(ex);

				// Propagate exception to caller.
				throw ex;
			}

			finally {
				// Reset common introspection caches in Spring's core, since we
				// might not ever need metadata for singleton beans anymore...
				resetCommonCaches();
				contextRefresh.end();
			}
		}
	}

ServletWebServerApplicationContext类

public final void refresh() throws BeansException, IllegalStateException {
		try {
			super.refresh();
		}
		catch (RuntimeException ex) {
			WebServer webServer = this.webServer;
			if (webServer != null) {
				webServer.stop();
			}
			throw ex;
		}
	}

SpringApplication类

private void refreshContext(ConfigurableApplicationContext context) {
		if (this.registerShutdownHook) {
			shutdownHook.registerApplicationContext(context);
		}
		refresh(context);
	}
public ConfigurableApplicationContext run(String... args) {
		StopWatch stopWatch = new StopWatch();
		stopWatch.start();
		DefaultBootstrapContext bootstrapContext = createBootstrapContext();
		ConfigurableApplicationContext context = null;
		configureHeadlessProperty();
		SpringApplicationRunListeners listeners = getRunListeners(args);
		listeners.starting(bootstrapContext, this.mainApplicationClass);
		try {
			ApplicationArguments applicationArguments = new DefaultApplicationArguments(args);
			ConfigurableEnvironment environment = prepareEnvironment(listeners, bootstrapContext, applicationArguments);
			configureIgnoreBeanInfo(environment);
			Banner printedBanner = printBanner(environment);
			context = createApplicationContext();
			context.setApplicationStartup(this.applicationStartup);
			prepareContext(bootstrapContext, context, environment, listeners, applicationArguments, printedBanner);
			refreshContext(context);
			afterRefresh(context, applicationArguments);
			stopWatch.stop();
			if (this.logStartupInfo) {
				new StartupInfoLogger(this.mainApplicationClass).logStarted(getApplicationLog(), stopWatch);
			}
			listeners.started(context);
			callRunners(context, applicationArguments);
		}
		catch (Throwable ex) {
			handleRunFailure(context, ex, listeners);
			throw new IllegalStateException(ex);
		}

		try {
			listeners.running(context);
		}
		catch (Throwable ex) {
			handleRunFailure(context, ex, null);
			throw new IllegalStateException(ex);
		}
		return context;
	}
public static ConfigurableApplicationContext run(Class<?>[] primarySources, String[] args) {
		return new SpringApplication(primarySources).run(args);
	}
public static ConfigurableApplicationContext run(Class<?> primarySource, String... args) {
		return run(new Class<?>[] { primarySource }, args);
	}
public static void main(String[] args) {
        SpringApplication.run(SpringBootSecurityApplication.class, args);
    }

本文来自互联网用户投稿,该文观点仅代表作者本人,不代表本站立场。本站仅提供信息存储空间服务,不拥有所有权,不承担相关法律责任。如若转载,请注明出处:/a/2272.html

如若内容造成侵权/违法违规/事实不符,请联系我们进行投诉反馈qq邮箱809451989@qq.com,一经查实,立即删除!

相关文章

类ChatGPT开源项目的部署与微调:从LLaMA到ChatGLM-6B

前言 近期&#xff0c;除了研究ChatGPT背后的各种技术细节 不断看论文(至少100篇&#xff0c;100篇目录见此&#xff1a;ChatGPT相关技术必读论文100篇)&#xff0c;还开始研究一系列开源模型(包括各自对应的模型架构、训练方法、训练数据、本地私有化部署、硬件配置要求、微调…

Java代码是如何被CPU狂飙起来的?

&#x1f4e3;&#x1f4e3;&#x1f4e3;&#x1f4e3;&#x1f4e3;&#x1f4e3;&#x1f4e3; &#x1f38d;大家好&#xff0c;我是慕枫 &#x1f38d;前阿里巴巴高级工程师&#xff0c;InfoQ签约作者、阿里云专家博主&#xff0c;一直致力于用大白话讲解技术知识 &#x…

安全防御之防火墙篇(二)

目录 1.防火墙如何处理双通道协议&#xff1f; 2.防火墙如何处理NAT&#xff1f; 3.防火墙支持哪些NAT技术&#xff0c;主要应用的场景是什么&#xff1f; 4.当内网PC通过公网域名解析访问内网服务器的时候&#xff0c;会存在什么问题&#xff0c;如何解决&#xff1f;请详细…

【MySQL】CentOS编译安装MySQL5.7实战

前言 这篇文章是关于MySQL编译安装的&#xff0c;重点掌握的是编译的过程&#xff0c;以及体会排错的痛苦。出错在所难免&#xff0c;最重要的是要有一颗不放弃的心。 本文收录于《数据库入门与精通》专栏, 本专栏写作的过程中&#xff0c;联合了csdn几位DBA大佬&#xff0c;…

SpringBoot整合Kafka(包含Kafka_2.12-3.3.1单节点安装,kafka可视化程序efak v3.0.1安装)

SpringBoot整合Kafka&#xff08;包含Kafka_2.12-3.3.1单节点安装&#xff0c;kafka可视化程序efka v3.0.1安装&#xff09;kafka、efak安装包下载kafka安装资源下载&#xff1a;下载tgz安装包&#xff1a;http://archive.apache.org/dist/kafka/ //解压 tar -zxvf /home/soft/…

自定义类型的超详细讲解ᵎᵎ了解结构体和位段这一篇文章就够了ᵎ

目录 1.结构体的声明 1.1基础知识 1.2结构体的声明 1.3结构体的特殊声明 1.4结构体的自引用 1.5结构体变量的定义和初始化 1.6结构体内存对齐 那对齐这么浪费空间&#xff0c;为什么要对齐 1.7修改默认对齐数 1.8结构体传参 2.位段 2.1什么是位段 2.2位段的内存分配…

【java】笔试强训Day1

⛳选择题 1.在 Java 中&#xff0c;存放字符串常量的对象属于 &#xff08; &#xff09;类对象 A、Character B、String C、StringBuffer D、Vector &#x1f648;大家觉得答案是什么呢 &#x1f649;答案是…

GPT-4发布:人工智能新高度,以图生文技术震撼,短时间内挤爆OpenAI模型付费系统

“GPT-4&#xff0c;起飞&#xff01;”今日凌晨1点&#xff0c;OpenAI正式推出史上最强大的GPT-4文本生成AI系统 GPT-4&#xff1a;人工智能的新里程碑 你可能已经听说过GPT-3&#xff0c;它是一种能够生成自然语言文本的强大模型&#xff0c;可以用来回答问题、写文章、编程…

【Java SE】变量的本质

目录一. 前言二. 变量(variable)2.1 性质2.2 变量类型2.2.1 核心区别2.3 变量的使用三. 总结一. 前言 一天一个Java小知识点&#xff0c;助力小伙伴更好地入门Java&#xff0c;掌握更深层次的语法。 二. 变量(variable) 2.1 性质 变量本质上就是代表一个”可操作的存储空间”…

STL库中list的迭代器实现痛点分析

前文本篇文章准备换个模式&#xff0c;之前都是先详解模拟实现&#xff0c;但是模拟实现的基本逻辑大多数老铁都是明白的&#xff0c;所以我们这次主要讲解STL库中list的独特性&#xff0c;也就是模拟实现中的重难点文末有模拟实现的源码一&#xff0c;list实现的特殊类list实现…

【pytorch】使用deepsort算法进行目标跟踪,原理+pytorch实现

目录deepsort流程一、匈牙利算法二、卡尔曼滤波车速预测例子动态模型的概念卡尔曼滤波在deepsort中的动态模型三、预测值及测量值的含义deepsort在pytorch中的运行deepsort流程 DeepSORT是一种常用的目标跟踪算法&#xff0c;它结合了深度学习和传统的目标跟踪方法。DeepSORT的…

WireShark如何抓包,各种协议(HTTP、ARP、ICMP)的过滤或分析,用WireShark实现TCP三次握手和四次挥手

WireShark一、开启WireShark的大门二、如何抓包 搜索关键字2.1 协议过滤2.2 IP过滤2.3 过滤端口2.4 过滤MAC地址2.5 过滤包长度2.6 HTTP模式过滤三、ARP协议分析四、WireShark之ICMP协议五、TCP三次握手与四次挥手5.1 TCP三次握手实验5.2 可视化看TCP三次握手5.3 TCP四次挥手5.…

PCL 使用ICP点云拼接

一、简介 ICP算法详解——我见过最清晰的解释_负壹的博客-CSDN博客 两个点集&#xff0c;source和target&#xff0c;target不变&#xff0c;source经过旋转&#xff08;Rotation&#xff09;和平移&#xff08;Translation&#xff09;甚至加上尺度&#xff08;Scale&#x…

大聪明教你学Java | 深入浅出聊 SpringBoot 中的 starter 机制

前言 &#x1f34a;作者简介&#xff1a; 不肯过江东丶&#xff0c;一个来自二线城市的程序员&#xff0c;致力于用“猥琐”办法解决繁琐问题&#xff0c;让复杂的问题变得通俗易懂。 &#x1f34a;支持作者&#xff1a; 点赞&#x1f44d;、关注&#x1f496;、留言&#x1f4…

网络安全横向移动指南

在网络安全方面&#xff0c;了解威胁参与者的工具、技术和思维过程非常重要。 一旦对手获得对网络的初始访问权限&#xff0c;横向移动允许他们通过破坏目标组织网络中的其他主机来扩展访问权限并保持持久性。 威胁行为者可以收集有关公司用户活动和凭据、重要数据位置的信息…

Spark - 继承 FileOutputFormat 实现向 HDFS 地址追加文件

目录 一.引言 二.源码浅析 1.RDD.saveAsTextFile 2.TextOutputFormat 3.FileOutputFormat 三.源码修改 1.修改文件生成逻辑 - getRecordWriter 2.允许目录存在 - checkoutputSpecs 3.全部代码 - TextOutputFormatV2 四.追加存储代码实战 五.总结 一.引言 Output d…

关于STM32用DMA传输UART空闲中断中接收的数据时无法接收数据问题以及解决办法

一、stm32 cube ide 配置 1、DMA串口接收数据的ide配置如下图所示 串口1相关的设置及printf函数的使用&#xff0c;这里没放&#xff0c;建议先实现串口打印功能 2、相关的知识点 普通模式和循环模式的区别在于&#xff0c;普通模式下&#xff0c;DMA只会接收一次数据&#x…

微前端(无界)

前言&#xff1a;微前端已经是一个非常成熟的领域了&#xff0c;但开发者不管采用哪个现有方案&#xff0c;在适配成本、样式隔离、运行性能、页面白屏、子应用通信、子应用保活、多应用激活、vite 框架支持、应用共享等用户核心诉求都或存在问题&#xff0c;或无法提供支持。本…

DS18B20温度传感器简介和1-Wire驱动程序

目录DS18B20简介DS18B20的两种供电方式64位ROM温度传感器1-Wire Bus简介DS18B20通信时序初始化ROM相关命令(后续包含任何数据交换的操作)功能相关命令(后续包含任何数据交换的操作)单个DS18B20读取温度值驱动多个DS18B20读取温度值驱动DS18B20简介 DS18B20数字温度计提供9位到…

学习系统编程No.7【进程替换】

引言&#xff1a; 北京时间&#xff1a;2023/3/21/7:17&#xff0c;这篇博客本来昨天晚上就能开始写的&#xff0c;但是由于笔试强训的原因&#xff0c;导致时间用在了做题上&#xff0c;通过快2个小时的垂死挣扎&#xff0c;我充分意识到了自己做题能力的缺陷和运用新知识的缺…